Timolol is the first glaucoma medication to be introduced in the last several decades. In preliminary studies, it has been shown to be apparently safer and more efficacious than the currently available topical glaucoma medications. This study is designed to test specifically the long term efficacy and safety of timolol. The study is divided into three parts: (1) A long term dose response study; (2) an additive study to see if timolol is additive with the currently available glaucoma medications and vice versa; and (3) a long term, 4 to 5 year follow-up study of the patients being treated with timolol. This last part is the most important for the establishment of the long term efficacy and level of safety of this drug; these patients will be followed with the most sophisticated ophthalmological techniques presently available.